Questions about the ECU controlled exhaust on E63

[Psilonaught]

still early in my ownership of an E63, so still getting used to it.

Today i noticed that the exhaust volume on start up, and for around 10 seconds was nice and loud, and then it dropped by about half. I sounded like a flap or valve was suddenly closing.

I have read on here and elsewhere that these cars don't in fact have have any such flaps, and that it is all ECU controlled.

So what exactly is happening when the sound lowers, and can it be defeated so it is always what loud?

I also read that sport or sport+ makes the exhaust louder than comfort. Is that true, I can't hear any difference??

I really don't want to risk altering the AMG sound so i want to avoid X/H pipe mods.

 

[st13phil]

On a cold start the turbo's are bypassed, the engine is deliberately overfuelled and the ignition timing altered in order to promote quick heating of the cat converters. After a few seconds the bypass closes and if you listen carefully you'll hear the turbo's spool up as the exhaust quietens.

So, in short, the engine starts from cold as a normally aspirated unit - if only for the first few seconds - which is why it's louder than normal.

 

[Psilonaught]

ok thanks I didn't know that

What about the difference between comfort and sport+ , should i be expecting to hear a volume difference?

 

[ShaunB]

ok thanks I didn't know that

What about the difference between comfort and sport+ , should i be expecting to hear a volume difference?

Ha - if you're using some revs on sport+ then on downshifts yes

 

[MancMike]

Comfort mode sets off in 2nd gear too.

 

[st13phil]

What about the difference between comfort and sport+ , should i be expecting to hear a volume difference?

No volume difference per se, but in Sport+ you get some pretty raucous downshift blips and pops and bangs on full-throttle upshifts

 

[Psilonaught]

Had more of an extended play today and I have to say I think the volume is actually just right. Just like my 645ci, the exhaust definitely gets louder as it heats up.

I was also impressed with the sound coming out the back with the pano roof and windows closed. The larger rear of the wagon amplifies the exhaust. And I got some fencing in there today he.

I'm going to put the cat among the pigeons and suggest the factory exhaust is perfect...

 

[bluestreak]

I tend to agree about factory exhaust, there, look! Two cats now [emoji16]

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